Backyard Aquaponics
A place to discuss aquaponics

We have a new system up and running with seedlings slowly establishing.The first fish were added 1 wk ago( 50 s/p fingerlings ). 3 medium sized marron have been in there happily for about 1 mth. Now the fish have slowly started dying 1 by 1. There is no gulping for air just the odd fish going mad before a slow death.There is a small build up of healthy green on the sides of the tank, plenty of air via bubblers and the system coming on hrly.The water was stired up 2 days ago when we tried ways of keeping the fish away from marron claws (yes they did get some).Ph level is about 6.2. Even the marron don't look happy this arvo. Any ideas, please help

Would be helpful to know your water parameters Kelly... do you have a test kit??..

Test for....

Ammonia, Nitrites, Nitrates, pH and water temperature...

How big is your fish tank?



Do you mean that the fish are dasing around and rubbing themselves on the bottom or sides of the tank... and "flashing" the sides/underbellies??



When you stirred it up.... was there a lot of matter suspended in the water??... has it cleared??

+1
Beat me by that much!Rupe

We only have a pool test kit that tests for free chlorine(0.5ppm), ph (6.2), and total Alkalinity ((40ppm). the water did get quite murky but has now cleared.Stiring up happened when we took the fish out for 24 hrs ( into clean rain water with airator) they are now bak in main tank (2500 lt)and have been for 24 hrs

Are there any injuries to the dead fish?
Or are there any obvious signs and symptoms?
Faye

Forgot to add :Fish don't seem to be rubbing just short bursts of frantic swimming/ jumping / running blind followed sometimes by laying upside down for a few seconds. Temperature going from 12 to 16 throughout the day

On the first 2 there were marron marks that's when we tried to separate them. All the rest ( about 10 ) have no obvious signs at all

Silver perch do not like sudden changes in water conditions from my experience. Do the fish have somewhere to be able to hide from the marron, or are they living under stress permanently.

Got a divider up from one side to the other made from flywire some fish have got through but those ones look good.

Would have thought perhaps ammonia was an issue.... but at pH 6.2 and your temps...

You could actually get away with a (relatively) high ammonia load....

Be more tempted to think that the fish are literally "stinging".... pH on the boderline for Silver Perch.... and possibly high nitrite levels.....

Regardless... I think I'd do an immediate 50% water change & ....to bring the pH back a bit... and lower any nitrites...

Then I'd salt at 3ppt.... both to alleviate nitrite toxicity (only really needs 1ppt) and for any ICH, or other parasites.... and as a general stress reliever and health tonic for the fish... (needs 3ppt)....

Salting (among other things) stimulates the product of slime coating... a ohysical barrier to any secondary infections such as fungus or bacteria....

I think you really need to buy a test kit rather than fly blind on these matters Kelly....

You could PM, email or call Joel at the BYAP shop at Jandarkot... and he'll get one to you...

Just to add... (your too quick guys)

I would definately go out ASAP and get a proper aquarium test kit. It wont be overly cheap but is going to give us and you the best idea
of what is going on.

At a minimum you will need ammonia, nitrite and nitrate testers. Do two or three tests of each and average the the results.
Post them up ASAP.

Can you increase the pump on duration or frequency?
Going from 3 medium sized marron to 50 sp is quite a big step. Don't forget that marron can survive in lower water conditions than SP.

I would do a 1/4 water change every couple of days if possible. Make sure you let the chlorine dissipate for a day in buckets or treat the water before adding it.

A quick test is to smell the water, does it smell like ammonia. Does it smell pungent?

We wont know exactly what is going on until we get the water test figures, but I hope this helps...

why has no one asked about the 0.5ppm free chlorine??????

.... didn't even register Steve... just noted that they had a test kit that measured it...

Kelly... noted you had the silvers in a small "rain water tank" for a while....

but are you dosing the tank with pool chemicals ... i.e chlorine...(or have you)....

Or did you fill the 2500ltr tank with straight tap water...

0.5ppm... what sort of levels affect fish Steve??

You may find its because they are too cold - fingerlings start to die at 15 deg c water temps.

Was just reasing through this thread for first time and was wondering why nobody asked about chlorine, until I got to Steve's post.

Need to get a test kit and find out what is going on. Also need to neutralise chlorine or chloramine in water before adding.